User equipment performance in carrier aggregation scenarios

Abstract

Methods, systems, and devices for wireless communication are described. A user equipment (UE) may receive a carrier aggregation (CA) configuration including at least a primary component carrier (PCC) and a secondary component carrier (SCC), where the PCC is configured for frequency domain duplexed (FDD) communications and the SCC is configured for time domain duplexed (TDD) communications. To determine whether sounding reference signal (SRS) carrier switching (e.g., between the PCC and the SCC) is appropriate, the UE may monitor performance metrics. If the performance metrics fail to satisfy corresponding thresholds, the UE may reduce an SRS periodicity. For instance, the UE may request that a network entity reduce the SRS periodicity. Alternatively, the UE may reduce a quantity of antennas used for the SRS transmissions. In other examples, the UE may initiate an interchange between the PCC and the SCC such that SRS carrier switching is no longer utilized.

What is claimed is: 
     
         1 . A user equipment (UE), comprising:
 one or more memories storing processor-executable code; and   one or more processors coupled with the one or more memories and individually or collectively operable to execute the code to cause the UE to:
 receive control signaling indicating a carrier aggregation configuration for a set of component carriers, the set of component carriers including at least a primary carrier configured for frequency domain duplexed communications and a secondary carrier configured for time domain duplexed communications; 
 monitor one or more performance metrics associated with communications at the UE; 
 transmit a UE assistance information message indicating a request to modify a configured periodicity of sounding reference signal (SRS) transmissions by the UE via the secondary carrier based at least in part on detecting that a performance metric of the one or more performance metrics satisfying a threshold value; and 
 communicating, via the secondary carrier, one or more SRS transmissions accord to a periodicity that is updated based at least in part on transmitting the UE assistance information message. 
   
     
     
         2 . The UE of  claim 1 , wherein, to monitor the one or more performance metrics, the one or more processors are individually or collectively operable to execute the code to cause the UE to:
 monitor the one or more performance metrics in accordance with a monitoring periodicity that is based at least in part on a coherence time associated with the UE.   
     
     
         3 . The UE of  claim 2 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the UE to:
 detect, after updating the periodicity and based at least in part on the monitoring, that at least one performance metric of the one or more performance metrics fails to satisfy the threshold value; and   communicating, via the secondary carrier, a second one or more SRS transmissions accord to the configured periodicity based at least in part on the at least one performance metric failing to satisfy the threshold value.   
     
     
         4 . The UE of  claim 2 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the UE to:
 detect, after updating the periodicity and based at least in part on the monitoring, that at least one performance metric of the one or more performance metrics fails to satisfy the threshold value;   transmit a second UE assistance information message indicating a second request to update the periodicity of the SRS transmissions by the UE via the secondary carrier based at least in part on the at least one performance metric failing to satisfy the threshold value; and   communicating, via the secondary carrier, a second one or more SRS transmissions accord to a second periodicity that is updated based at least in part on transmitting the second UE assistance information message.   
     
     
         5 . The UE of  claim 4 , wherein the second periodicity is the same as the configured periodicity. 
     
     
         6 . The UE of  claim 1 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the UE to:
 receive, in response to transmitting the UE assistance information message, a control message indicating the periodicity; and   update the configured periodicity to the periodicity based at least in part on receiving the control message.   
     
     
         7 . The UE of  claim 1 , wherein:
 the one or more performance metrics comprise at least one of an uplink buffer size at the UE, a rate at which the uplink buffer size at the UE increases, a block error rate associated with uplink communications at the UE, a path loss associated with the uplink communications at the UE, a downlink channel estimation obtained by the UE, a rank associated with downlink communications at the UE, a signal-to-noise ratio associated with the UE, or a combination thereof, and   the threshold value comprises at least one of a threshold uplink buffer size, a threshold rate at which the uplink buffer size at the UE increases, a threshold block error rate associated with the uplink communications at the UE, a threshold path loss value associated with the uplink communications at the UE, a threshold downlink channel estimation value, a threshold rank value associated with the UE, a threshold signal-to-noise ratio associated with the UE, or a combination thereof.   
     
     
         8 . The UE of  claim 1 , wherein the request to modify the configured periodicity comprises an indication of the periodicity. 
     
     
         9 . The UE of  claim 1 , wherein the request to modify the configured periodicity comprises a request to decrease the configured periodicity. 
     
     
         10 . The UE of  claim 1 , wherein the periodicity is less than the configured periodicity. 
     
     
         11 . A user equipment (UE), comprising:
 one or more memories storing processor-executable code; and   one or more processors coupled with the one or more memories and individually or collectively operable to execute the code to cause the UE to:
 receive control signaling indicating a carrier aggregation configuration for a set of component carriers for the UE, the set of component carriers including at least a primary carrier configured for frequency domain duplexed communications and a secondary carrier configured for time domain duplexed communications; 
 transmit, while operating in a first tracking area according to a first antenna switching capability of the UE, a first message requesting to perform a tracking area update (TAU) procedure based at least in part on detecting that a performance metric associated with communications at the UE satisfies a threshold value, wherein the first antenna switching capability of the UE corresponds to a first quantity of receive antennas supported by the UE for communications via the secondary carrier, and wherein the first message indicates a tracking area identifier for the TAU procedure corresponding to the first tracking area; 
 receive, in response to the first message, a request for the UE to indicate a capability of the UE; 
 transmit, in response to the request, a second message indicating a second antenna switching capability of the UE based at least in part on adjusting the first antenna switching capability of the UE to the second antenna switching capability of the UE, the second antenna switching capability of the UE corresponding to a second quantity of receive antennas supported by the UE for communications via the secondary carrier, wherein the second quantity of receive antennas is less than the first quantity of receive antennas; and 
 communicating, via the secondary carrier, one or more sounding reference signal (SRS) transmissions in accordance with the second quantity of receive antennas. 
   
     
     
         12 . The UE of  claim 11 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the UE to:
 monitor one or more performance metrics including the performance metric to detect that the performance metric satisfies the threshold value, wherein the monitoring is in accordance with a monitoring periodicity that is based at least in part on a coherence time associated with the UE.   
     
     
         13 . The UE of  claim 12 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the UE to:
 detect, after adjusting the first antenna switching capability of the UE to the second antenna switching capability of the UE and based at least in part on the monitoring, that at least one performance metric of the one or more performance metrics fails to satisfy the threshold value;   adjust the second antenna switching capability of the UE to the first antenna switching capability of the UE based at least in part on the at least one performance metric failing to satisfy the threshold value; and   communicating, via the secondary carrier, a second one or more SRS transmissions in accordance with the first quantity of antennas.   
     
     
         14 . The UE of  claim 11 , wherein:
 the performance metric comprises at least one of an uplink buffer size at the UE, a rate at which the uplink buffer size at the UE increases, a block error rate associated with uplink communications at the UE, a path loss associated with the uplink communications at the UE, a downlink channel estimation obtained by the UE, a rank associated with downlink communications at the UE, a signal-to-noise ratio associated with the UE, or a combination thereof, and   the threshold value comprises at least one of a threshold uplink buffer size, a threshold rate at which the uplink buffer size at the UE increases, a threshold block error rate associated with the uplink communications at the UE, a threshold path loss value associated with the uplink communications at the UE, a threshold downlink channel estimation value, a threshold rank value associated with the UE, a threshold signal-to-noise ratio associated with the UE, or a combination thereof.   
     
     
         15 . A user equipment (UE), comprising:
 one or more memories storing processor-executable code; and   one or more processors coupled with the one or more memories and individually or collectively operable to execute the code to cause the UE to:
 receive control signaling indicating a carrier aggregation configuration for a set of component carriers, the set of component carriers including at least a first carrier configured as a primary cell and a second carrier configured as a secondary cell, wherein the first carrier is configured for frequency domain duplexed communications and the second carrier is configured for time domain duplexed communications; 
 transmit a measurement report based at least in part on detecting that a performance metric associated with communications at the UE satisfies a first threshold value and that a difference value between a first signal strength measurement for the primary cell and a second signal strength measurement for the secondary cell satisfies a second threshold value, the measurement report including a first value corresponding to the first signal strength measurement and a second value corresponding to the second signal strength measurement plus an offset value; 
 receive control signaling triggering a handover procedure to switch the primary cell to be associated with the second carrier and the secondary cell to be associated with the first carrier based at least in part on the measurement report including the second value corresponding to the second signal strength measurement plus the offset value; and 
 communicate one or more sounding reference signal (SRS) transmissions via the second carrier based at least in part on performing the handover procedure. 
   
     
     
         16 . The UE of  claim 15 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the UE to:
 monitor one or more performance metrics including the performance metric to detect that the performance metric satisfies the first threshold value.   
     
     
         17 . The UE of  claim 15 , wherein:
 the first signal strength measurement comprises a first ratio of a received signal strength indicator (RSSI) for the primary cell to a reference signal received power (RSRP) for the primary cell,   the second signal strength measurement comprises a second ratio of an RSSI for the secondary cell to an RSRP for the secondary cell, and   the difference value comprises a difference between the first ratio and the second ratio.   
     
     
         18 . The UE of  claim 15 , wherein the second value is greater than the first value. 
     
     
         19 . The UE of  claim 18 , wherein the first value comprises the first signal strength measurement minus a second offset value. 
     
     
         20 . The UE of  claim 15 , wherein:
 the performance metric comprises at least one of an uplink buffer size at the UE, a rate at which the uplink buffer size at the UE increases, a block error rate associated with uplink communications at the UE, a path loss associated with the uplink communications at the UE, a downlink channel estimation obtained by the UE, a rank associated with downlink communications at the UE, a signal-to-noise ratio associated with the UE, or a combination thereof, and   the first threshold value comprises at least one of a threshold uplink buffer size, a threshold rate at which the uplink buffer size at the UE increases, a threshold block error rate associated with the uplink communications at the UE, a threshold path loss value associated with the uplink communications at the UE, a threshold downlink channel estimation value, a threshold rank value associated with the UE, a threshold signal-to-noise ratio associated with the UE, or a combination thereof.   
     
     
         21 . A method for wireless communication by a user equipment (UE), comprising:
 receiving control signaling indicating a carrier aggregation configuration for a set of component carriers, the set of component carriers including at least a primary carrier configured for frequency domain duplexed communications and a secondary carrier configured for time domain duplexed communications;   monitoring one or more performance metrics associated with communications at the UE;   transmitting a UE assistance information message indicating a request to modify a configured periodicity of sounding reference signal (SRS) transmissions by the UE via the secondary carrier based at least in part on detecting that a performance metric of the one or more performance metrics satisfying a threshold value; and   communicating, via the secondary carrier, one or more SRS transmissions according to a periodicity that is updated based at least in part on transmitting the UE assistance information message.   
     
     
         22 . The method of  claim 21 , wherein monitoring the one or more performance metrics comprises:
 monitoring the one or more performance metrics in accordance with a monitoring periodicity that is based at least in part on a coherence time associated with the UE.   
     
     
         23 . The method of  claim 22 , further comprising:
 detecting, after updating the periodicity and based at least in part on the monitoring, that at least one performance metric of the one or more performance metrics fails to satisfy the threshold value; and   communicating, via the secondary carrier, a second one or more SRS transmissions according to the configured periodicity based at least in part on the at least one performance metric failing to satisfy the threshold value.   
     
     
         24 . The method of  claim 22 , further comprising:
 detecting, after updating the periodicity and based at least in part on the monitoring, that at least one performance metric of the one or more performance metrics fails to satisfy the threshold value;   transmitting a second UE assistance information message indicating a second request to update the periodicity of the SRS transmissions by the UE via the secondary carrier based at least in part on the at least one performance metric failing to satisfy the threshold value; and   communicating, via the secondary carrier, a second one or more SRS transmissions according to a second periodicity that is updated based at least in part on transmitting the second UE assistance information message.   
     
     
         25 . The method of  claim 24 , wherein the second periodicity is the same as the configured periodicity. 
     
     
         26 . The method of  claim 21 , further comprising:
 receiving, in response to transmitting the UE assistance information message, a control message indicating the periodicity; and   updating the configured periodicity to the periodicity based at least in part on receiving the control message.   
     
     
         27 . The method of  claim 21 , wherein:
 the one or more performance metrics comprise at least one of an uplink buffer size at the UE, a rate at which the uplink buffer size at the UE increases, a block error rate associated with uplink communications at the UE, a path loss associated with the uplink communications at the UE, a downlink channel estimation obtained by the UE, a rank associated with downlink communications at the UE, a signal-to-noise ratio associated with the UE, or a combination thereof, and   the threshold value comprises at least one of a threshold uplink buffer size, a threshold rate at which the uplink buffer size at the UE increases, a threshold block error rate associated with the uplink communications at the UE, a threshold path loss value associated with the uplink communications at the UE, a threshold downlink channel estimation value, a threshold rank value associated with the UE, a threshold signal-to-noise ratio associated with the UE, or a combination thereof.   
     
     
         28 . The method of  claim 21 , wherein the request to modify the configured periodicity comprises an indication of the periodicity. 
     
     
         29 . The method of  claim 21 , wherein the request to modify the configured periodicity comprises a request to decrease the configured periodicity. 
     
     
         30 . The method of  claim 21 , wherein the periodicity is less than the configured periodicity.